Protect one file with a passphrase you control
Private File Encryptor creates an authenticated encrypted .prvenc file locally in your browser. It is useful when you want a password-protected container for a file before transferring or storing it through your chosen method. The application does not upload the selected file to an encryption server and does not provide a cloud sharing account or recover a forgotten passphrase.
Choose Encrypt, select the file, enter a long unique passphrase and confirm it. Keep the passphrase separately from the encrypted download. Sending both together in the same message can defeat the practical purpose of password protection even when the cryptography itself works as intended.
Understand what is protected
The format uses AES-256-GCM authenticated encryption. A key is derived from the passphrase with PBKDF2-HMAC-SHA256 and 310,000 iterations, using a random sixteen-byte salt. Encryption also uses a random twelve-byte IV, and the container header is authenticated. These are properties of the current local format, not a promise that a weak password becomes strong.
A long, unique passphrase is still essential. Avoid a client name, a common phrase or a short password reused elsewhere. Someone who obtains the encrypted file can attempt guesses without asking PRVKIT for permission. Key derivation increases the work per guess but does not remove that risk or compensate for an easily guessed secret.
The tool protects the file content within its supported container. It does not hide that an encrypted file exists, protect the device where the original remains or control what an authorized recipient does after decryption. Transfer channels, filenames, backups and shared folders can reveal context outside the encrypted payload.
Keep an independent recovery plan
There is no account-based password reset for the encrypted content. A lost passphrase cannot be recovered by support. Keep an appropriate secure record and test the decryption workflow before relying on the encrypted file as your only available copy.
That test should use the saved container, not merely an in-memory success message. Download it, switch to Decrypt, select the .prvenc file and enter the passphrase. Compare the restored file with the original through normal opening or, when appropriate, a known hash. Keep the original until you have established that the workflow serves your storage or transfer needs.
Do not delete data merely because an encryption operation completed. This tool does not perform secure erasure of your disk, remove copies from backups or revoke a file already distributed. Those are separate decisions and processes with different risks.
Authentication failures are intentionally unspecific
During decryption, a wrong passphrase and altered ciphertext both fail authentication. The application cannot reliably tell you which one happened simply from that failure. Check the passphrase carefully and verify that you selected the intended complete container, but do not assume the error proves tampering or proves that the password alone is wrong.
Do not try to force an output from a container that failed authentication. A malformed, incomplete or unsupported file should remain a failure rather than being treated as partially trusted plaintext. Keep the original failed file if you need to investigate a transfer problem, and avoid exposing the passphrase or sensitive content in a support message.
A successful decryption establishes the supported container's integrity under the derived key. It is not a signature proving who created the plaintext or whether its content is safe. A malicious file can be encrypted just as an ordinary document can. Continue to use appropriate file-opening precautions after decryption.
Choose a transfer method separately
PRVKIT creates local output; it does not send the file to a recipient. Use your chosen transfer service or storage location, and communicate the passphrase through an appropriately separate channel. The application does not certify that a particular provider or messaging arrangement meets your obligations.
Consider whether the plaintext itself should be minimized first. If a screenshot contains information the recipient should never see, redact it before encryption. Encryption limits who can open the file, while redaction changes what an authorized recipient receives. They solve different problems and can be used together deliberately.
For a PDF, verify any redacted copy before protecting it. For a photograph, check visible identifiers and supported metadata as appropriate. Encrypting an unreviewed source does not make its contents suitable for everyone who later learns the passphrase.
Work within the browser budget
The configured source ceiling is 40 MiB. An encrypted container has additional header and authentication overhead, so its size differs from the original. The application also uses an estimated working-memory budget; file bytes alone do not describe every buffer needed during encryption and output creation.
Local processing still relies on a capable browser and its cryptographic APIs. Website code loads from the site, and a compromised browser or device can expose plaintext or a passphrase before encryption. Browser-local operation is useful, but it is not a claim of anonymity, complete endpoint security or immunity from extensions.
Use the tool only for files you are authorized to handle. The format is PRVKIT's supported container, not a ZIP password, PDF password or universal substitute for other encryption formats. A recipient needs a compatible decryption path and the correct passphrase; a new extension alone does not make the file interoperable everywhere.
Check the saved result before relying on it
Confirm that the encrypted download has completed and is the file you intended. A download request is not proof of finished saving. Test decryption from the saved bytes and keep a clear distinction between plaintext, ciphertext and any restored copy during review.
File Inspector & Hash can compare bytes with an expected SHA-256 digest when you have a trusted reference. Redact Image and Redact PDF address content that should not be disclosed even to the eventual recipient. Choose the next workflow according to that specific need, save the current result and never include a passphrase in a public report or filename.